[Dreamerish*~]

Technetium-99m

Benefits:

• Useful in diagnosis in medicine. It can assist in the diagnosis of blood clots, tumors (including brain tumors), thyroid abnormalities and bone diseases.
• It can also be used to assess the damage of the heart after heart-attacks.
• It has a half-life of 6 hours, which is short enough to emit intensive radiation, but also short enough so that the patient is not exposed to radiation for a prolonged period of time.

Problems:

• Has a short half-life of 6 hours (this one works both ways). This means that it must be produced at the hospital in which it will be used. Technetium-99m is produced from the radioactive decay of molybdenum-99. So the only nuclear reactor in Australia (Lucas Heights) must deliver the molybdenum-99 to hospitals needing technetium-99m, with the molybdenum-99 gradually decaying into technetium-99m on the road. This creates a bit of an inconvenience regarding transportation.
• As with all radioisotopes, radiation is harmful to all living organisms. Radiation is capable of causing tissue damage, cancer and genetic errors. Even though the benefits of particular radioisotopes may outbalance the disadvantages, all radiation are harmsul, regardless of the uses of the radioisotope.

Americium-241

Benefits:

• Is widely used in smoke alarms to assist detection of fire. It does this by emitting alpha particles which ionise the air surrounding the smoke detector. The ions are then accelerated to an electrode inside the detector, and the resulting electrical current measured. When smoke (soot) is present in the air, the ions are lost and do not reach the electrode. This reduction of electrical current triggers an alarm.
  
• Has a half-life of 432 years, which means it wouldn't have to be changed very often.
• Alpha particles are quite large in comparison to beta and gamma (which aren't particles in the first place). They can be stopped by a piece of paper, therefore are not as harmful.
  

Problems:

• The half life of 432 years is a problem as after old smoke detectors are disposed, they americium inside them will continue to emit radiation, causing environmental problems.
• See the second disadvantage of technetium-99m.